Calculates the average, minimum, maximum, median, and standard deviation of the scores

How to write a java program to calculates the average, minimum, maximum, median, and standard deviation of the scores ?

Solution:

import java.util.Arrays;
import java.util.Scanner;
import javax.swing.JOptionPane;
/*This project calculates the average, minimum, maximum, median, and standard deviation of the scores. */
public class ScoreCalculator3
{
   public static void main(String[] args)
   {    
       Scanner in = new Scanner(System.in); // declare and create a Scanner object which will read user input from keyboard
       
       int scores[] = new int[100];
       int answer;
       
        do
        {
            double input;
            int numScores = 0;
            double sum = 0;
            double average = 0.0;
            double min = 100;
            double max = 0;
            double median = 0;
            double stdev = 0;
            System.out.println("Please enter scores on a single line and type a -1 at the end ");
            input = in.nextDouble();
            
             if (input == -1) {
                System.out.println( "Number of scores  : 0");
                System.out.println("The average score  : 0.00");
                System.out.println("The minimum score  : 0");
                System.out.println("The maximum score  : 0");
                System.out.println("The median         : 0");
                System.out.println("The standard deviation: 0");
                answer = JOptionPane.showConfirmDialog(null, "Do you want to continue?"); 
                in.nextLine();
                continue;
            }

            while (input != -1) {
                // Add input to scores array
                scores[numScores] = (int)input;
                
                // Increment numScores
                numScores++;
                input = in.nextDouble();
            }
            in.nextLine();
            //average = (double)(sum/(double)numScores);
            
            numScores = loadArray(scores);
            
            // Print output
            System.out.println("Number of scores   : " + loadArray(scores));
            System.out.printf("The average score: %.2f\n", findAverage(scores, numScores));
            System.out.println("The minimum score  : " + findMinimum(scores, numScores));
            System.out.println("The maximum score  : " + findMaximum(scores, numScores));
            System.out.println("The median score  : " + findMedian(scores, numScores));
            System.out.println("The standard deviation : " + findSTD(scores, numScores, findAverage(scores, numScores)));   

            answer = JOptionPane.showConfirmDialog(null, "Do you want to continue?");
        } while (answer == 0);
       
       
   }
   public static int loadArray(int[] arr) // load array
   {    
       int length = 0;
       for (int i = 0; i < 100; i++) {
           if (arr[i] != -1) {
               length++;
               
           } else{ 
               break;
           }
       }
       
       return length;
   }

   /**
    * Compute the average scores
    * @param arr 
    * @param numberOfScores 
    * @return average
    */
   public static double findAverage(int[] arr, int numberOfScores)
   {
       int sum = 0;
       for (int i = 0; i < numberOfScores; i++) {
           sum = sum + arr[i];
       }
       return sum / numberOfScores;
   }
   /**
    * Compute the minimum scores for that courses
    * @param arr
    * @param numberOfScores
    * @return minimum
    */
   public static int findMinimum(int[] arr, int numberOfScores) 
   {
       int min = 100;
       for (int i = 0; i < numberOfScores; i++) {
           // If element is lesser than min
           if (arr[i] < min) {
               // Declare new min
               min = arr[i];
            }
        }
        return min;
   }
   /**
    * Compute the maximum scores for that courses
    * @param arr
    * @param numberOfScores
    * @return maximum
    */
   public static int findMaximum(int[] arr, int numberOfScores)
   {
       int max = 0;
       for (int i = 0; i < numberOfScores; i++) {
           // If element is more than max
           if (arr[i] > max) {
               // Declare new max
               max = arr[i];
            }
        }
        return max;
   }
   /**
    * Compute the standard deviation for that courses
    * @param arr
    * @param numberOfScores
    * @param avg
    * @return STD
    */
   public static double findSTD(int[] arr, int numberOfScores, double avg)
   {
       double sum_diff = 0;
       for (int i = 0; i < numberOfScores; i++) {
           sum_diff = sum_diff + Math.pow(arr[i] - avg, 2);
       }
       return Math.sqrt(sum_diff / numberOfScores);
   }
   /**
    * Compute median scores for that courses
    * @param arr
    * @param numberOfScores
    * @return median
    */
   public static double findMedian(int[] arr, int numberOfScores) 
   {
      Arrays.sort(arr); 
      
      // If even number of scores
      if (numberOfScores % 2 == 0) {
          int mid = numberOfScores / 2;
          return (arr[mid-1] + arr[mid])/2;
      }
        // If odd number of scores
        else {
            int mid = numberOfScores / 2;
            return arr[mid];
        }
      
      /*
      int mid = arr.length/2;
      if (arr.length%2 == 1) {
          return arr[mid];
      } else
      {
          return (arr[mid-1] + arr[mid]) / 2.0;
      }
      */
          
        
   }
   public static void printArray(int[] arr, int length) 
   {
       for (int i =0; i < length; i++)
       {
           System.out.print(arr[i] + " ");
       }
       System.out.println(); 
   }
}

Learn More :

Median

Minimum

Score

Average

Maximum

Standard Deviation

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